1. Field of the Invention
The present invention generally relates to the field of information retrieval and access, and more particularly to a method for compressing a large table of information to be easily viewed by various types of digital devices having unique display capabilities.
2. Discussion of the Art
As the Internet becomes increasingly popular, more and more non-PC types of devices, such as smart phones and PDAs (personal digital assistants), are being used to access information on the Internet. These devices are generally connected to the Internet either by wired or wireless connections. Similar to the laptop or notebook computers, these non-PC devices tend to be mobile (i.e. handheld) devices. They generally have unique and often limited hardware capabilities, both in their display and processing capabilities. As such, it is very difficult for a content serve to organize information into a table so that it can be easily browsed by the users of PCs and various non-PC devices having disparate display and processing capabilities. This problem is particularly severe when the table contains a large number of rows and columns that cannot be fit into the limited display of the viewing device.
It is very important, however, that most applications are capable of displaying a large table of information, especially as more and more back-end databases are made available through the Internet. For example, more and more people are using not only PCs but also their PDAs to access their e-mails, to search or scan product items from an electronic catalog, and to search airline flight schedules on the Internet. For many users, the electronic mailbox can contain a large list of unread e-mails. The list of product items from a catalog can be exceedingly large as well. The potentially large list of e-mails as well as product items is very difficult to display effectively on a PDA or even on a regular PC. Further, such a long list of items is also very difficult for a user to browse.
Various image compression techniques have been proposed to represent an image at many different levels of detail. For example, in xe2x80x9cA Framework for Optimization of a Multiresolution Remote Image Retrieval System,xe2x80x9d by A. Ortega et al., Proceedings of IEEE InfoCom, 1994, a system was disclosed to transmit images (including video) in multiple resolutions. Also, in xe2x80x9cThe JPEG Still Picture Compression Standard,xe2x80x9d by G. Wallace, IEEE Transactions on Consumer Electronics, vol. 38, no. 1, February 1992, the JPEG image compression standard was described to represent images at multiple resolutions.
In the area of text processing, various automatic abstracting schemes have been disclosed to perform document summarization. For example, U.S. Pat. No. 5,077,668 discloses a method for producing an abstract of a document. The method is capable of producing a concise abstract indicative of the content of the document automatically. U.S. Pat. No. 5,638,543 discloses a method in which regions of a document, such as sentences and blocks of sentences, are scored and classified based on their scores. An abstract of the document can then be formed based on the classified sentences. U.S. Pat. No. 5,867,164 discloses a real-time interactive document summarization system which allows a user to continuously control the amount of details to be included in a document summary.
These references all assume that the data in a document is of a uniform data type. However, a table can contain a list of attributes/columns having a plurality of data types. As a result, table summarization (i.e. compression) cannot be performed by simply applying a uniform compression or abstracting function, as described in the prior art.
Thus, there is a need for a flexible and dynamic table summarization method to reduce not only the number of rows but also the width and/or the number of columns so that a table can be formed from a plurality of data types, and then displayed and easily browsed by users having different kinds of viewing devices.
The present invention discloses a method for flexible and dynamic table summarization. Table summarization as used herein may be generally defined as a method of compressing the rows and columns of an input table containing data having a variety of data formats, to generate an output table having a reduced row/column count and/or format such that the output table is manageable for viewing on a plurality of viewing devices each having unique display capabilities.
Briefly stated, the table summarization method involves performing a row reduction operation and a column reduction operation on an input table. Row reduction generally involves collapsing groups of original rows from an input table into a smaller number of resultant rows according to a set of predefined row reduction rules. Column reduction may be performed in a number of ways including, for example, simply dropping a column, reducing a data type to a shorter format, and merging multiple columns into a single column.
In an exemplary embodiment of the present invention, a data network connects a plurality of viewing devices with content servers, and proxy servers act as intermediary communicating nodes connecting the content servers to the viewing devices. In an exemplary implementation, a viewing device typically makes a request to browse an object containing one or more tables of information. When a viewing device makes an object request, a set of pre-defined row and column reduction rules (i.e. meta-data), uniquely associated with and specific to each table, is accessed to perform table summarization, when necessary, on one or more of the tables contained within the requested object. That is, table summarization is only required when it is determined that one or more tables require compression or reduction to accommodate the viewing device.
In accordance with the present invention, a method for transforming a table into a summarized table includes the steps of defining meta-data to be associated with said table, said meta-data comprising row reduction and combination rules, receiving a request to view the table from a viewing device, transforming the table in response to the request to view the table by the viewing device in accordance with said meta-data.
The present invention also provides a method for further defining column value transformation to be included as part of said defined meta-data.
In addition, preferred embodiments may also include defining a viewing preference ruleset that will supplement the meta-data rules. That is, the user viewing preference ruleset will be used as an adjunct for those rules not explicitly specified in the meta-data.
Yet another element of a preferred embodiment includes a provision for including the specifications of the viewing device to perform summarization of the data structure.